The technical field generally relates to delivering chemicals downhole in a wellbore. Certain types of chemicals are preferentially mixed at a treatment location or close to the treatment location. For example, certain mixed chemicals produce strong acids or have highly viscous reaction products, and it may be desirable to minimize equipment contact with the mixed chemicals, or to minimize the operational complexity of mixing and delivering the chemicals. Presently available methods for delivering chemicals directly to a downhole location have drawbacks, including the requirement to prepare for the chemical delivery with special equipment or procedures before the chemical delivery is needed, difficulty in ensuring that the chemicals are delivered to a desired depth, and difficulty in ensuring the chemicals mix at the desired depth. Therefore, further technological developments are desirable in this area.